This invention relates to an agent for desensitizing man and/or animals against an allergen comprising liposomes that comprise an allergen. This invention also relates to a method for desensitization by administration of such an agent into man and/or animals.
Allergy is an ailment that affects millions of individuals worldwide. Attempts to desensitize an individual against a material that causes an allergic response (hereafter designated as an "allergen") by injection of measured dosages of the allergen heretofore has failed to achieve complete relief of allergy symptoms reproducibly in all allergic individuals. An allergic response is a term of art and has a well-defined meaning. Within the context of the present invention, an allergic response includes, in particular, at least one of the features of (1) production of an abnormally high level of IgE in an individual's serum, (2) immunologic interaction between an allergen, an individual's IgE and leukocytes, resulting in release of histamines, (3) production of hives, rashes, wheel and flare and similar dermatological manifestation of hypersensitivity and (4) anaphylaxis.
Until the present invention, an individual who wishes to become desensitized against an allergen has to submit himself/herself to injections of measured doses of the allergen, first administered at weekly or biweekly intervals, then gradually decreases to bimonthly or monthly intervals throughout the year. Such injections generally commence with a small dose of the allergen and then gradually increasing the dosage until a maximally-tolerated maintenance dose is achieved. The individual is then kept on a maintenance dose of the allergen indefinitely or until the individual no longer exhibits an allergic reaction to the allergen.
Liposomes have been used recently as carriers of vaccines, e.g., a vaccine against a malarial parasite as described by Alving et al., in Vaccine, 4:166-172 (I986) and a vaccine against Epstein-Barr ("EB") virus as described by Alving in "Liposomes as Carriers for Vaccines" in LIPOSOMES FROM BIOPHYSICS TO THERAPEUTICS, M. J. Ostro ed. (Marcel Dekker, Inc. N.Y. 1987).
Liposomes have also been used as carriers of drugs, e.g., amphotericin B as described by Lopez-Berestein et al., in J. Infect. Dis. 151:704-710 (1985) and an antimitotic agent as described by Coune et al., in Cancer Treat. Rep. 67:1031-1033 (1983).
Until the present invention, there has been no report of using liposome comprising an allergen to desensitize an individual against the allergen.